Radiation Safety and Regulations- Domain 2

deterministic radiation

have a threshold dose below which they don't occur, and the severity increases with dose beyond that threshold.

stochastic

are probabilistic, meaning the risk of the effect increases with dose, but the effect itself is the same (an all-or-nothing effect)

deterministic effects

skin burns, hair loss, cataracts, and radiation sickness, observed shortly after exposure, effects are predictable

stochastic effects

cancer, leukemia, and genetic mutations, can manifest years after the initial exposure, occur by chance. 

acute effects

200 rem, radiation sickness (nausea, vomit, diarrhea, etc.)

cataract induction

500 rem single dose, but 800 rem protracted time

fertility effects

400 rem to ovaries (50 rem for temporary amenorrhea)

late effects

period of patency then onset of effect, can be several years later

genetic effects

mutation is an inherited change in a gene, a finite segment of DNA within a chromosome

developmental effects

25 rem single exposure, effects to fetus can be seen (growth and developmental retardation, congenital abnormalities, and prenatal or neonatal death)

occupational limit- whole body

5 rem (50 mSv)

occupation limit- eyes

15 rem (150 mSv)

occupational limit- any organ or tissue

50 rem (500 mSv)

occupational limit- extremity/skin

50 rem (500 mSv)

occupational limit- general public

0.1 rem (1 mSv)

occupational limit- embryo/fetus

0.5 rem (5 mSv) for entire pregnancy

short term vs long term radiation effects

short-term radiation effects, like acute radiation syndrome, occur within a few days or weeks after high doses, while long-term effects, such as cancer, can develop months or even years later, depending on the level of exposure. 

acute radiation syndrome- ARS

this occurs with high doses of radiation over a short period, causing symptoms like nausea, vomiting, diarrhea, and potentially death. 

Radiosensitivity

can damage DNA, damaged cells may die or stop dividing, can kill or slow down cancer cells

ALARA is both a

safety principle and regulatory requirement

as low as reasonably acheivable

Radiation surveys (area monitoring) frequency

daily where radioactive material was used

survey meters and well counters qc

daily

wipe survey frequency and limits

weekly

<2000 dpm/100cm²

Trigger levels for survey meters must be set at no less than _____ for restricted areas.

5 mrem/hr (0.05 mSv/ hr)

Trigger levels for survey meters must be set at no less than _____ for unrestricted areas.

0.2 mrem/hr (2uSv/hr)

Trigger level for wipes

22,000 dpm/ 100 cm²

Removable contamination of a radioactive package containing beta, gamma, low toxicity alpha cannot exceed

24 dpm/cm² (7200 for 300 cm²)

Removable contamination of a radioactive package containing alpha emitters cannot exceed

2.4 dpm/cm² (720 dpm for 300 cm²)

A GM counter is good for surveys of contamination because

it has a rapid response time and can detect a wide range of exposure rates

NRC requires that a survey meter is capable of detecting exposure rates from

0.1 mrem/ hr - 100 mrem/ hr

(Met by GM counters)

The pancake probe on a survey meter allows

survey of a bigger area

GM counters are not as accurate as

portable ionization chambers (cutie pie)

The well counter uses _________ crystals to detect very low activities of radioactive material (wipe tests)

thallium-activated sodium-iodide

How often is GM counter calibrated

annually (checks before each use for battery, background, constancy)

How often is well counter/ uptake probe calibrated

Constancy - daily

Energy resolution - quarterly

Efficiency - annually

How often is dose calibrator calibrated

Constancy - daily

Linearity - quarterly

Accuracy - quarterly

Geometry - installation/ repair

How long must you keep record of personnel exposure according to NRC regulations

duration of employment, + 30 years

film badges

most common type, using film and filters to detect radiation dose levels, not reusable

TLDs

use crystals like lithium fluoride (LiF) or calcium fluoride (CaF₂) to store and measure radiation exposure, reusable

OSLs

use aluminum oxide to detect radiation dose levels and are highly sensitive, making them suitable for pregnant women

ring badges

monitor extremity radiation exposure, use thermoluminescent dosimetry (TLD) technology to measure ionizing radiation

collar badge

a whole-body radiation dosimeter badge for monitoring radiation exposure from X-rays and gamma radiation, can be a TLD or OSL

dosimeter reports

reviewed and provided monthly or quarterly, annual report provided

declaration of pregnancy

A radiation worker who is pregnant or planning to become pregnant may formally declare their pregnancy to their employer in writing, must wear fetal monitor

PPE in nuclear medicine

lab coat, gloves, syringe shield

syringes must be labeled, if you can’t see through syringe shield, the shield must be labeled.